1. Unit 1. Day 5.

2. Please get out paper for today’s lesson
Name
Date
Period
Topic: Multiplying Integers
7.NS.A.2 Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers

3. What is an integer? Real Irrational π, e, 2 Rational
-3.24, 2/3, 6.71, -5/2, …
Integers
-1, -2, -3, -4, …
Irrational
π, e, 2
Whole
Natural
1, 2, 3, 4, …

4. Review “additive inverse”
Review meaning of Multiplication
Multiplying integers
Add/Subtract vs. multiplication

5. − + − − − + + + − − − − − − − − + + + + + + + + “additive inverse”
−1 + 1= + − − −
−3 +3= + + + − − − − − − − −
8 + −8 = + + + + + + + +

6. “additive inverse”

8. Review “additive inverse”
Review meaning of Multiplication
Multiplying integers
Add/Subtract vs. multiplication

9. Multiply ×5 = 15 3 3 3 3 3 + + + + 1 2 3 4 5 6 7 8 9 10 11 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11

10. Multiply ×8 5 5 5 5 5 5 5 5 = 40 + + + + + + + 1 2 3 4 5 6 7 8 9 10 11 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11

12. Review “additive inverse”
Review meaning of Multiplication
Multiplying integers
Add/Subtract vs. multiplication

13. Multiply −2×4 −2 −2 −2 −2 = −8 + + +

14. Multiply −3×6 −3 =
−18 −3 −3 −3 −3 −3 + + + + +

15. = ? 6 Multiply. −2 × −3 −2×5= −10 −2×4= −8 −2×3= −6 −2×2= −4 −2×1= −2
−2×0=
−2×−1= 2
−2×−2= 4
−2×−3= 6
−2∙−3
−2∙−1
−2∙5
−2∙4
−2∙3
−2∙2
−2∙1
−2∙0
−2∙−2 1 2 3 4 5 6 7 8 9 10 11 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11

16. = 20 ? Multiply. −4 × −5 −4×5= −20 −4×4= −16 −4×3= −12 −4×2= −8 −4×1=
−4×0=
−4×−1= 4
−4×−2= 8
−4×−3= 12
−4×−4= 16
−4×−5= 20

17. 3×5 = 15 5×8 =40 −2×4 =−8 −3×6 =−18 −2×−3=6 −4×−5=20 Same signs:+
3×5 = 15
5×8 =40
−2×4 =−8
−3×6 =−18
−2×−3=6
−4×−5=20
Same signs:+
Different signs:−

18. + ∙ + = + + ∙− =− − ∙− = + − ∙+ =− 4∙6= + 24 4∙−6= − 24 −4∙−6= + 24
Integer
Multiplication
− ∙− = +
− ∙+ =−
−4∙−6= + 24
−4∙6= − 24

19. −21 18 −36 + ∙ + =+ − ∙ − =+ 25 + ∙ − =− − ∙ + =− 42 −24 28 −13
Example A: −3∙7 =
𝐼𝑛𝑡𝑒𝑔𝑒𝑟
𝑀𝑢𝑙𝑡𝑖𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛
Example B: = 18
Same signs:+
Different signs:−
Example C: ∙−4 =
−36
+ ∙ + =+
− ∙ − =+
+ ∙ − =−
− ∙ + =−
Example D: −5∙−5 = 25
Example E: 6∙7= 42
Example F: −8 =
−24
Example G: −7∙−4= 28
Example H: −1×13=
−13

20. Please get out the assignment from last class.
Please get out your notes from yesterday.
Please complete the quiz, and write your answers in the answer box

21. Review “additive inverse”
Review meaning of Multiplication
Multiplying integers
Add/Subtract vs. multiplication

22. Subtract and keep bigger sign
Example I: −
−8+3= + −
−8∙3= − 24 8 − 3 5 5 − − − − − − − − + + +
+ ∙ + =+
− ∙ − =+
+ ∙ − =−
− ∙ + =−
Same signs:
Add and keep the sign
Different signs:
Subtract and keep bigger sign

23. Subtract and keep bigger sign
Example J: −
−7+9= + +
−7∙9= − 63 9 − 7 2 2 − − − − − − − + + + + + + + + +
+ ∙ + =+
− ∙ − =+
+ ∙ − =−
− ∙ + =−
Same signs:
Add and keep the sign
Different signs:
Subtract and keep bigger sign